Prioritize and maintain sensitive or at-risk species or communities

EASTERN: Many species are projected to decline as a result of climate change. For example, northern and boreal species are widespread in northern portions of the Midwest and Northeast, but are likely to lose habitat because they are already at the southern extent of their range. Other species may be more vulnerable due to their dependence on a narrow range of site conditions. Identifying and maintaining sensitive or at-risk species as long as possible may help them persist until new long-term sites can be located and populated. 

WESTERN: Many species are projected to decline as the changing climate causes physiological stress and habitat shifts. For example, some subalpine species in the Sierra are likely to experience a reduction in suitable habitat as temperatures increase, even as other species become more competitive. Likewise, coastal species dependent on a narrow range of site conditions, such as regular, heavy fog, may be more vulnerable as precipitation changes in form and pattern. Identifying and maintaining sensitive or at-risk species as long as possible may help them persist until new long-term sites can be accessed and/or populated.

Refugia are areas that have resisted ecological changes occurring elsewhere, often providing suitable habitat for relict populations of species that were previously more widespread. Climate refugia are often formed by topography (e.g., north sides of slopes, or sheltered ravines), proximity to large water bodies, or connection to groundwater. An excellent example of this are the 75 or so giant sequoia (Sequoiadendron giganteum) groves scattered across the Sierra Nevada mountain range that have persisted in sites that are relatively more mesic and have reliable summer moisture. Springs and other sites with strong connections to groundwater can provide cool water refugia, and are critical habitat for a variety of California’s threatened and endangered species. During previous periods of rapid climate change, at-risk populations persisted in refugia that avoided extreme impacts. These populations allowed species to persist until more favorable climatic conditions returned and species were able to expand into newly available habitats. This strategy seeks to identify and maintain habitats that: (1) are on sites that may be better buffered against climate change and short-term disturbances, and or (2) contain communities and species that are at risk across the greater landscape.